TRENDS: BRINGING GEOPHYSICAL TECHNOLOGY INTO SHARPER FOCUS

Hugh W. Hardy
Interpretation Consultants Inc.
Houston

All of us are acutely aware of the problems that have provided a worldwide excess of crude oil and a domestic natural gas "bubble" and caused a significant decrease in the value of a barrel of crude oil and its equivalent in natural gas. Many U.S. petroleum companies have discovered that their "worst case" oil price scenarios of several years ago are actually optimistic in today's market.

Now that the initial shock has abated, the petroleum industry must begin a search for solutions. There are some who would turn to the federal government with the request that a variable import tax be assessed on each barrel of crude oil or refined product brought into the U.S.

To me, such an action-though possibly necessary-is undesirable because of the artificiality it would create in the price of oil, and I doubt that any of the revenue generated by such a tax would go towards assuring our domestic industry's survival. Also, I would anticipate that the Organization of Petroleum Exporting Countries nations might perceive such a tax as a direct challenge and be prompted to react in retribution.

Some companies have sought to avoid the high cost of finding petroleum by acquiring-often at bargain prices-other companies that hold significant petroleum reserves. Over the short haul, this can afford some immediate relief, but in reality it is unproductive because the dollars used to make such a purchase (or spent by a company to prevent a hostile takeover) often come from exploration, drilling, and production budgets. And it must be realized that money spent in purchasing established production does not add to this country's available petroleum reserves.

NEED FOR EFFICIENCY

If this nation is going to continue to enjoy its current standard of living, have a positive growth, and maintain an adequate petroleum reserve to meet our security needs and support our industrial development, neither conservation, energy alternatives, nor dependence on imported oil are satisfactory answers. The obvious answer is to be more efficient-smarter-in our exploration and production activities so that our cost of finding and producing a barrel of oil can be reduced to a value that will allow us to more nearly compete with today's low prices.

First, it is essential that we improve our drilling success ratio; or, to put it another way, quit drilling expensive dry holes.

Second, it is highly desirable that the structure or trapping mechanism of the potential reservoir be accurately defined.

Third, the ability to determine probable formation fluid content-i.e., to differentiate between natural gas and crude oil, before drilling-would allow the operator to spend his money on prospects that best met his objectives.

Fourth, it would be very helpful if information regarding probable formation pressure, reservoir saturations, and fluid contacts was available in guiding the explorationist in selecting the best drilling location ... and the driller in planning his mud and casing programs.

And finally, in existing fields, the compilation of all this information would be extremely valuable in the exploitation efforts, which include the location of development wells, field extension wells, and subsequently in directing the tertiary recovery program.

Providing this information from geophysical activities requires the effective application of existing technology and use of technology from the point of planning the data acquisition; shooting or vibrating the lines; processing the field data; making the initial structural interpretation, emphasizing stratigraphic and depositional environment techniques; producing appropriate models of the prospect; and communicating the results to the decision makers.

The preceding statement, I believe, makes us realize that managers, often from other disciplines, should be given an opportunity to understand the basic ideas of our science and its capacities.

RECENT DEVELOPMENTS

Some of the more recent technological developments which are rapidly being accepted in our industry include vertical seismic profiling (VSP), which allows us to use seismic energy to "look ahead" of the drill bit. This technology holds the potential to answer that age-old question which plagues drillers, "Did we drill deep enough?"

In the more conventional application of new technology, new seismic programs have been created that essentially allow the data processor to image seismic reflections under salt dome overhangs and in the shadow zones encountered near geologic fault planes. And there is considerable progress being made in recording seismic data with long in-line offsets and using the amplitude response to determine reservoir characteristics of the rock types; the gas/oil, gas/water, and oil/water contacts; and even an estimate of the saltwater saturation of oil or gas bearing formations. This technology is basically an outgrowth of the old "bright" or "dim" spot phenomena.

When we begin to combine the efforts of the geophysicist and geologist to produce a true explorationist, more technology is required. For example, an advanced interpretive modeling system exists that generates very comprehensive two- or three-dimensional models while allowing the geologist and geophysicist to input their specific information, thus producing a true geoseismic model.

This system has recently been made interactive, thus displaying the results on a color TV monitor as the geological and geophysical parameters are changed. The same software programs, which initially required relatively large computers, have been adapted to smaller, economical workstations.

The impact of these workstations is obvious when you attend Society of Exploration Geophysicists or American Association of Petroleum Geologists conventions. The exhibit booths that attract the largest crowds are those showing these little "marvels" of technology.

The idea of each company, or office, having its own "exploration machine"-capable of displaying and manipulating seismic data, geologic information, well logs, and even historical and current production information-is highly intriguing. Also, the ability to "network" these computers, access a common database, record seismic information from around the world in real time, and transfer such information between offices (even those in different cities) is truly desirable in our very dynamic industry.

LEARNING, COMMUNICATING

Learning to use this new technology to its best advantage will be a challenge to our industry as a whole.

And that challenge creates another one almost as difficult-learning how to communicate this knowledge, not only to nontechnical managers but even among geophysicists. I have often heard the comment that we need translators when our researchers discuss a problem with our operations people.

Our industry has borrowed from the disciplines of acoustics, mathematics, rock mechanics, physics atmospherics, computer science, communications theory, radar imaging, photography, hydrology, geology, and even xerography in producing the information we use. The introduction of new technology in any one of these disciplines can produce a completely new focus for geophysicists. We are light years away from the relatively simple beginnings when cloistered monks observed earthquakes by interpreting stylus scratches on a smoked glass and were referred to as seismologists.

Today, geophysicists-using all of the technology we can create, beg, borrow, or purloin-are applying that technology in the search for the energy so essential to our survival.

But current economic and political conditions make it necessary that we refine that technology even more in the near future, if our profession is to survive and meet its obligations to the American people.

Copyright 1991 Oil & Gas Journal. All Rights Reserved.